A flat tyre may be replaced with a spare wheel stowed in a compartment on the vehicle specially designed for the purpose, e.g. under the floor of the boot, in the case of a passenger car.
The spare wheel, however, is bulky and takes up space in the boot that could be used for other purposes.
Moreover, the weight of the spare wheel makes it difficult to assemble, particularly in the case of a large heavy-duty vehicle spare wheel.
Repair and inflation kits are also known, for repairing a flat tyre without taking it off the vehicle.
Known kits comprise a container of sealing fluid, and a dedicated compressor connected to the container of sealing fluid. In the event of a flat tyre, the container is connected to the tyre by a hose, and the dedicated compressor then activated.
The compressed air injects the sealing fluid into the tyre, and inflates it once the viscosity of the fluid increases and seals the puncture in the tyre.
The dedicated compressor normally used in known kits is a reciprocating type powered by an electric motor. Compressors of this type are relatively noisy and bulky, particularly when designed for inflating large heavy-duty vehicle tyres.
U.S. Pat. No. 6,766,834 discloses a unit according to the preamble of claim 1. Such unit, however, needs to be adapted when the pressure source is a pneumatic circuit of the vehicle.